Vehicle mounted accessory assembly

ABSTRACT

A vehicle mounted accessory unit assembly is provided that is removably mountable to a vehicle, the accessory assembly including a support frame having a first and second portion that are connected at a pivot point, with the pivot point enabling forces to be directed in such a way as to minimize the stresses on the vehicle to which the accessory unit assembly is attached. The accessory unit assembly further includes a wheel assembly to further minimize the stresses on the vehicle. The wheel assembly preferably includes a ground engaging wheel, a mounting member, a spring assembly and a dampener. A steering dampener is also utilized.

RELATED APPLICATION

This application claims priority from prior filed provisionalapplication Ser. No. 60/026,072, filed Sep. 13, 1996.

FIELD OF THE INVENTION

The invention relates to vehicle mounted accessory assemblies, and moreparticularly, to vehicle mounted accessory assemblies that are supportedby both the vehicle and a ground engaging wheel.

BACKGROUND OF THE INVENTION

Vehicle mounted accessory assemblies such as snowplows have beentraditionally mounted to heavy duty trucks. Such snowplows are notnormally mounted to lightweight vehicles such as automobiles, lighttrucks and sport utility vehicles because the weight of the snowplow andits supporting frame tends to over stress the vehicle and, particularly,over stress the vehicle's front end suspension.

Casters have been used for many years to support vehicle mountedsnowplows after detachment from the vehicle. One problem withtransporting snowplows having casters is an oscillation or shimmy thatoccurs when the ground engaging wheel is off set from a center alignmentsuch as by an uneven surface, obstruction or the like. This oscillationcan be undesirable as well as stress the structure of the snowplowassembly decreasing its operational life.

SUMMARY OF THE INVENTION

The invention provides for a vehicle mounted accessory assembly that isremovably mountable to a vehicle. The assembly includes a support frameto which an accessory unit such as a snowplow blade and an actuator issecured. The support frame includes a first frame portion and a secondframe portion connected to each other at a pivot point remote from thevehicle. The pivot point enables forces to be directed in such a way asto minimize the stresses on the vehicle to which the accessory assemblyis mounted.

The vehicle mounted accessory assembly further includes a groundengaging wheel to absorb some of the impact on the accessory unit andtherefore minimize the stresses on the vehicle. The wheel is highwayrated such that it engages the ground when the accessory unit is beingtransported on the vehicle and when the accessory unit is being used forits intended application. The wheel is mounted to the support frame by awheel mounting assembly. The wheel mounting assembly includes a mountingmember, a spring and a dampener. The spring and dampener limit the rangeof movement of the wheel. The wheel mounting member may also include asteering dampener having one end secured to the mounting member andhaving a second end secured to the support frame. The king pin dampenerminimizes and eliminates oscillation of the ground engaging wheel.

It is an object of the present invention to provide a new and improvedvehicle mounted accessory assembly.

It is another object of the present invention to provide a vehiclemounted accessory assembly that minimizes the stresses on a vehicle towhich it is mounted and particularly, minimizes stresses in thevehicle's front end suspension.

It is another object of the present invention to provide a vehiclemounted accessory assembly that utilizes a two portion pivoting supportframe.

It is another object of the present invention to provide a vehiclemounted accessory assembly that utilizes a ground engaging wheel tosupport the accessory unit and minimize the forces on the vehicle bothwhen the unit is in use and when the unit is being transported on thevehicle.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a ground engaging wheel with awheel mounting assembly which utilizes a dampener and a spring.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a ground engaging wheel inwhich there is a positive stop on the movement of the wheel in both theupward and the downward vertical directions.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a ground engaging wheel inwhich there is dampening on the upward and downward movement of thewheel.

It is another object of the present invention to provide a vehiclemounted accessory assembly having a frame that includes a pivot pointthat directs plowing forces into a ground engaging wheel.

It is another object of the present invention to provide a vehiclemounted accessory assembly wherein the pivot point of the accessory unitis remote from the vehicle.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a highway rated groundengaging wheel with a dampener to minimize oscillations of the wheel.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a ground engaging wheel with adampener in operational engagement with the rotating king pin of thewheel and in engagement with a frame of the vehicle mounted accessoryassembly.

It is another object of the present invention to provide a vehiclemounted accessory assembly which includes a ground engaging wheel with adampener in operational engagement with the rotating king pin of thewheel to provide rotational dampening.

It is another object of the present invention to provide a vehiclemounted accessory assembly wherein the assembly is mounted to thevehicle under the vehicle near the front axle.

Other features and advantages of the invention will become apparent tothose of ordinary skill in the art upon review of the following drawing,detailed description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a vehicle mounted accessory assembly includinga ground engaging wheel and with an attached snowplow blade in a bladedown position;

FIG. 2 is a side view of the vehicle mounted accessory assemblyincluding the ground engaging wheel and with the attached snowplow bladein a blade up position;

FIG. 3 is a perspective view of a support frame of the vehicle mountedaccessory assembly;

FIG. 4 is a perspective view of a pivot frame with the attached snowplowblade;

FIG. 5 is a perspective view of a carriage, the ground engaging wheeland the wheel mounting assembly;

FIG. 6 is plan view of a plow mount;

FIG. 7 is a perspective view of a vehicle mount adjacent a vehicle'sframe horns;

FIG. 8 is an exploded perspective view of the ground engaging wheel andwheel mounting assembly;

FIG. 9 is a side view of the ground engaging wheel and the wheelmounting assembly;

FIG. 10 is a view taken along line 10--10 of FIG. 9;

FIG. 11 is a view taken along line 11--11 of FIG. 10;

FIG. 12 is a perspective view of a portion of the carriage, the groundengaging wheel and the wheel mounting assembly; and

FIG. 13 is a perspective view of a portion of the carriage, the wheelmounting assembly, and a king steering dampener.

Before one embodiment of the invention is explained in detail, it is tobe understood that the invention is not limited in its application tothe details of construction and the arrangement of components set forthin the following description or illustrated in the drawings. Theinvention is capable of other embodiments and of being practiced orbeing carried out in various ways. Also, it is to be understood that thephraseology and terminology used herein is for the purpose ofdescription and should not be regarded as limiting.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings, there is shown a vehicle mountedaccessory unit assembly 10 embodying the invention. The accessory unitassembly 10 can be used with a variety of different accessory units suchas, for example, a snowplow blade, sweeper, saltspreader and vacuum. Theaccessory unit assembly 10 will be hereafter described in conjunctionwith a snowplow blade. However, it should be noted that the vehiclemounted accessory assembly is not limited to only that type of accessoryunit.

Referring to FIGS. 1 and 3, the accessory unit assembly 10 includes asupport frame 12. The support frame 12 includes a first portion orcarriage 14 and a second portion or pivot frame 16. The carriage 14 andthe pivot frame 16 are pivotally connected by a pair of pivot pins 18such that the pivot frame 16 pivots or rocks about a pivot axis 19 withrespect to the carriage 14.

With specific reference to FIGS. 3 and 5, the carriage 14 includes apair of spaced side rails 20. Each side rail 20 has a first end 22 and asecond end 24. A projection 26 extends outwardly from the first end 22of each side rail 20. Each projection 26 has therethrough an aperture28. A pair of generally V-shaped support rails 30 and 32 extend betweenand above the side rails 20. Each rail 30 and 32 is at an angle withrespect to a perpendicular to the respective side rail 20 with thatangle preferably on the order of approximately 45-65 degrees, and mostpreferably 57 degrees.

A mounting rail 36 extends between the rails 30 and 32. The mountingrail 36 is preferably U-shaped in cross-section and has therethrough acircular aperture 37. A mounting plate 38 is positioned below themounting rail 36 (FIG. 12). The mounting plate 38 includes an aperture39 that is aligned with the aperture 37 of the mounting rail 36. Acylindrical member 40 extends upwardly from the mounting plate 38 and isaligned with the aperture 39 of the mounting plate 38 and the aperture37 of the mounting rail 36. The aperture 39, cylindrical member 40 andaperture 37 defined a bore 41.

In the snowplow blade application, the mounting rail 36 partiallysupports an actuator designed to raise and lower a snowplow blade.Preferably, the actuator is hydraulic. With reference to FIG. 3, themounting rail 36 supports a conventional hydraulic power unit 42. Aactuator 44 such as a hydraulic cylinder depends from and isoperationally connected to the hydraulic power unit 42.

As shown in FIG. 5, a pair of light fixture assemblies 67 is secured tothe carriage 14. Each light fixture assembly 67 includes support rails68 and a headlamp 69.

Referring back to FIGS. 3 and 4, the pivot frame 16 in the preferredembodiment is generally O-shaped in configuration. It should be noted,however, that the pivot frame 16 can have other configurations inaddition to the illustrated O-shape, such as rectangular. Specifically,the pivot frame 16 includes first and second generally C-shaped frames70 and 72. The frame 70 includes a first end 74, a second end 76 and acenter portion 78 therebetween. A pair of spaced upwardly extendingprojections 82 extend upwardly from the center portion 78. Eachprojection 82 has therethrough an axially aligned aperture 84.

The frame 72 includes a first end 86, a second end 88 and a centerportion 90 therebetween. The frame 70 and the frame 72 are fixedlysecured together, such as by welding, by aligning the end 74 of theframe 70 with the end 88 of the frame 72. Similarly, the end 76 of frame70 is aligned with the end 86 of the frame 72 and fixedly securedtogether, such as by welding, to maintain this orientation. Preferably,the frame 70 is oriented at an angle with respect to the frame 72 withthat angle being preferably on the order of generally 10 to 30 degreesand more particularly on the order of approximately 20 degrees.

As best shown in FIGS. 1 and 3, the carriage 14 and the pivot frame 16are pivotally connected with pivot pins 18 which define the pivot axis19. Preferably, the projections 26 of each side rail 20 interengage withthe pivot pin 18 to pivotally connect the carriage 14 to the pivot frame16. After the carriage 14 and the pivot frame 16 are pivotallyconnected, an end 98 of the actuator 44 is secured to the projections 82of the center portion 78 of the frame 70 of the pivot frame 16. Theactuator 44 is secured to the projections 82 through use of a fastener100 and the apertures 84 in the projections 82.

Referring now to FIGS. 3 and 4, the accessory unit assembly 10 furtherincludes an accessory mount or quadrant 102 secured to the pivot frame16. The quadrant 102 includes an elongate arm 104 having a mountingassembly 106 on each end. Each mounting assembly 106 includes agenerally L-shaped bracket 108 secured to the arm 104. Each bracket 108includes a first leg 110 and a second leg 112. The leg 110 hastherethrough an aperture 114. A pair of projections 116 extend outwardlyfrom the second leg 112 and quadrant 102. Each projection 116 hastherethrough an axially aligned aperture 118. A pair of generallyU-shaped brackets 120 are attached to and extend upwardly from the arm104.

A central bracket 124 extends outwardly from the central portion 90 offrame 72. The bracket is generally U-shaped and houses a central portionof quadrant 102. The quadrant 102 is pivotally connected to bracket 124using a suitable fastener such as a pivot pin.

As best shown in FIG. 4, the quadrant 102 is secured to the pivot frame16. Specifically, the center portion 90 of the frame 72 is positioned inthe passageway 126. A pair of actuators or angle rams 128 extend fromthe pivot frame 16 to the quadrant 102. A first end 130 of each ram 128is pivotally connected to the frame 72 with a bracket 132 and a fastenersuch as a pivot pin 134. A second end 136 of each ram 128 is positionedbetween the bracket 120 and the arm 104 and pivotally connected with asuitable fastener such as pivot pin 138.

Continuing to refer to FIG. 4, a plow blade assembly 142 is pivotallyconnected to the quadrant 102. The plow blade assembly 142 includes theplow blade 144 which is pivotally connected to the quadrant 102 at themounting assemblies 106 at each end of the arm 104. A portion 146 of theplow blade is positioned between the projections 116 and a fastener suchas 148 maintains the portion 146 and the projections 116 in thisorientation. The plow blade assembly 142 further includes a pair of tripsprings 150. A first end 152 of each spring 150 interengages with theplow blade 144. A second end 154 of each spring 150 interengages withthe aperture 114 in the respective mounting assembly 106.

It should be noted that the quadrant 102 can be of varyingconfigurations depending upon the type of accessory unit used. The roleof the quadrant 102 is to secure the chosen accessory unit to the pivotframe 16.

As shown in FIGS. 1 and 6, the support frame 12 is removably secured toa vehicle 46 with a plow mount 48. The plow mount 48 enables the pivotaxis 19 to be moved further outwardly from the front end of the vehicle46. The plow mount 48 includes a pair of spaced generally parallel sidemembers 50 and a cross member 54 extending therebetween. The members 50and 54 are oriented so that the plow mount 48 is generally C-shaped. Apair of mounting plates 56 extend outwardly from the cross member 54 ina direction away from the side members 50.

As shown in FIG. 1, the plow mount 48 is secured to the carriage 14through use of the mounting plates 56. One mounting plate 56 is securedto each side rail 20 with a suitable fastener such as a nut and bolt.

Referring now to FIG. 7, a vehicle mounting member 58 is utilized tosecure the accessory unit assembly 10 to the vehicle 46. Preferably, themounting member 58 is fixedly secured to the vehicle's frame horns 59 inthe front portion of the vehicle 46 with suitable fasteners. Themounting member 58 includes a cross member 60 and a pair of mountingbrackets 61 on each end of the cross member 60. The mounting brackets 61each include a pair of generally parallel plates 62 and 63 with oneplate 62 having therein a V-shaped recess and the other plate 63 havingtherethrough an aperture. When the accessory unit assembly 10 is to besecured to the vehicle 46, the plow mount 48 is pivotally connected tothe mounting member 58 such as through the use of a pivot pin.

Preferably, the mounting member 58 is positioned near the front axle ofthe vehicle 46 so as to be a distance from the bumper under the vehicle46. As shown in FIG. 6, for convenience, a remote latching mechanism 64is attached to each side member 50 (only one of which is shown in FIG.6) and enables securing of the accessory unit assembly 10 to the vehicle46 without a user having to crawl under the vehicle 46 to insert a pivotpin through each side member 50 and through a respective portion of thevehicle mounting member 58.

The remote latch mechanism 64 as shown in FIG. 6 is operated by movementa hitch arm 65. When the end of each side member 50 of the plow mount 48is positioned between the respective pair of plates 62 and 63 of thevehicle mounting member 58, movement of the hitch arm 65 in thedirection of the respective side member 50, moves a pivot pin 66outwardly from the side member 50 and through the aperture in the plate63 to secure the accessory unit assembly 10 to the vehicle 46. Likewise,a latch mechanism 64 on the other side member 50 of the plow mount 48would be actuated to move the hitch pin 66 into engagement with theaperture in the plate 63. The hitch arm 65 is held in this positionthrough use of a locking pin preferably on the cross member 54.

To release the accessory unit assembly 10 from the vehicle 46 using theremote latch mechanism 64, the respective locking pins are released sothat the respective hitch arms 65 can be moved away from the respectiveside members 50 thus freeing the hitch pins 66 from the apertures in therespective plates 63 and enabling the accessory unit assembly 10 to bemoved free of the vehicle 46.

FIG. 1 depicts the accessory unit assembly 10 with attached plow bladeassembly 142 in a blade down position. In this blade down position, thelower edge of the snowplow blade 144 is either contacting the ground oris in close proximity to the ground.

When it is desired to raise the snowplow blade 144 such as whentransporting the accessory unit assembly 10, when repositioning thesnowplow blade 144 or when stacking snow, the snowplow blade 144 ismoved to its blade up position as illustrated in FIG. 2.

With reference to FIGS. 1 and 2, the snowplow blade 144 is moved fromits blade down position to its blade up position using the actuator 44.When the actuator 44 is extended by the hydraulic power unit 42 andhydraulically locked in the extended position, the actuator 44 causesthe frame 70 of the pivot frame 16 to move downwardly. Due to the angledconnection between the frame 70 and the frame 72 and the pivotconnection between the pivot frame 16 and the carriage 14 at pivot axis19, downward motion of the frame 70 causes upward motion of the frame72. In turn, upward motion of the frame 72 causes upward motion of thequadrant 102 and the plow blade assembly 142 thus moving the plow blade144 upwardly. The degree to which the blow blade 144 is raised iscontrolled by the degree to which the actuator 44 is extended.

With the pivot axis 19 of the accessory unit being forward of thevehicle bumper, the vehicle bumper does not limit the range of motion ofthe accessory unit such as snowplow blade 144. Further, with the pivotaxis 19 forward and clear of the vehicle bumper, less stresses aretransferred to the vehicle 46. As shown in FIG. 1, the plow bladeassembly 142 is secured to the support frame 12 forward of the pivotaxis 19, forward being in a direction away from the vehicle 46 as if avertical plane intersected the pivot axis 19. The actuator 44 supportedby the carriage 14 is connected to the pivot frame 16 rearward of thepivot axis 19, rearward being in a direction toward the vehicle 46 as ifa vertical plane intersected the pivot axis 19.

To further minimize stresses on the vehicle, a ground engagable membersuch as a wheel assembly 160 is used in conjunction with the accessoryunit assembly 10. Other ground engagable members such as skids couldalso be utilized.

In the preferred embodiment, the wheel assembly 160 is particularlyshown in FIGS. 8 through 13. The wheel assembly 160 helps support theweight of the accessory unit assembly 10 during transportation on thevehicle 46 thus minimizing stress to the vehicle 46 caused by the weightof the accessory unit. Preferably, during accessory unit use, the wheelassembly 160 looses contact with the ground due to the operation of theactuator 44. Alternately, the wheel assembly 160 can maintain contactwith the ground during accessory unit use.

Referring now to FIGS. 8 through 11, the wheel assembly 160 includes aground engaging wheel 162 having an axis of rotation 164 and a hub 166.The wheel 162 is preferably highway rated such that the wheel 162 is incontact with the ground when the accessory unit is being transported onthe vehicle 46. Various types of wheels can be used such as wheels ratedwith a high speed pneumatic tire, such as, for example, an 8×33/4 wheelwith a 480×8 C rated tire from Nielsen Wheel of Milwaukee, Wis.

The wheel assembly 160 further includes a mounting assembly 168. Themounting assembly 168 includes a first mounting member and a secondmounting member. The first mounting member includes a support plate 170.A king pin 172 extends upwardly from the plate 170 along an axis 171. Apair of spaced legs 174 and 176 depend from the plate 170. The legs 174and 176 are spaced so as to enable the wheel 162 to be positionedtherebetween. A generally U-shaped yoke 178 is secured to the legs 174and 176. The yoke 178 extends outwardly from the legs 174 and 176 andincludes two legs 180 and 182 and a web 184 therebetween. A firstsupport plate 186 extends between the legs 180 and 182. A second supportplate 188 extends inwardly from the leg 180 toward the leg 182. Thesupport plate 186 has therein two apertures 190 and 192.

The second mounting member includes a pair of link arms 194 and 196.Each link arm 194 and 196 has a first end aperture 198, a second endaperture 200 and a center portion 202. The center portion 202 of thelink arm 194 is pivotally connected to the leg 174 such as by a pivotpin 204 at a pivot axis 206 and the center portion 202 of the link arm196 is pivotally connected to the leg 176 such as by a pivot pin 208 atthe pivot axis 206. The first end aperture 198 of each link arm 194 and196 is aligned with the hub 166 of the wheel 162 with a pin 210 alongthe axis of rotation 164. The pivot axis 206 is therefore not axiallyaligned with the axis of rotation 164 of the wheel 162 and is forward ofthe axis of rotation 164 in the direction the yoke 178 extends from thelegs 174 and 176. A support member or fastener 212 such as a boltsecured with a nut extends through the spaced second end apertures 200of the link arms 194 and 196.

Continuing to refer to FIGS. 8 through 11, the wheel assembly 160further includes a dampener such as shock absorber 214 and a springassembly 216 housed within the yoke 178. The shock absorber 214 is of aconventional hydraulic type such as small bore series from Arvin RideControl of Toronto, Canada. The shock absorber 214 includes a housing218 that is fixed to the support plate 188. The shock absorber 214further includes a rod 220 operationally connected to the housing 218.An end 224 of the rod 220 is pivotally connected to the fastener 212that extends between the link arms 194 and 196. The rod 220 extendsthrough and is moveable in the aperture 192 in the support plate 186.

The spring assembly 216 is housed adjacent the shock absorber 214. Thespring assembly 216 include a spring bar 226, a shaft 228 and a spring230. The shaft 228 includes a first end 232 that is fixed to the springbar 226. The shaft 228 extends downwardly from the spring bar 226through the aperture 190 in the support plate 186 and is pivotallyconnected to the fastener 212. The spring 230 is housed between thespring bar 226 and the support plate 186 and surrounds the shaft 228.One end of the spring 230 is in contact with the spring bar 226 and theother end of the spring 230 is in contact with the support plate 186.Preferably, the spring 230 is a compression spring.

As best shown in FIGS. 9 and 12, to connect the wheel assembly 160 tothe support frame 12 and, particularly, to the carriage 14, the king pin172 is positioned through the bore 41 so that a portion of the king pin172 extends upwardly from the cylindrical member 40. The king pin 172 issecured in this position, for example, using a fastener such as a cotterpin. In this orientation, the wheel assembly 160, and specifically theking pin 172, is allowed to pivot within the bore 41 along the axis 171.

In operation, the accessory unit assembly 10 and wheel assembly 160perform as follows. When vehicle is transporting the accessory unitassembly 10 and the wheel 162 encounters an obstacle (bounce condition),the wheel 162 is forced in an upward direction. The movement of thewheel 162 in turn causes movement of the link arms 194 and 196 whichpivots about the pivot axis 206 and causes the second end apertures 200of the link arms 194 and 196 to move downwardly. When the second endapertures 200 of the link arms 194 and 196 move downwardly, the fastener212 with rod 220 and shaft 228 pivotally connected thereto also movesdownwardly. This causes the spring 230 to be compressed due to thespring bar 226 and the shaft 228 moving downwardly with the fastener212. The fully compressed spring 230 acts as a positive stop for thewheel assembly 160 when encountering the obstacle. The shock 214 extendsto dampen the bounce of the wheel 162.

When the obstacle is removed (rebound condition), the second endapertures 200 of the link arms 194 and 196 move upwardly and eventuallycontact the bottom of the support plate 186 and act as another positivestop. The shock 214 retracts to dampen the rebound of wheel 162.

In a preferred embodiment, a castor wheel steering dampening assemblysuch as king pin dampener assembly 240 is utilized. As particularlyshown in FIGS. 12 and 13, the dampener assembly 240 includes a mountingblock or stabilizer mount 242 and a dampener such as shock absorber 244.The stabilizer mount 242 is preferably rectangular. A mounting boss 256extends upwardly on the mount 242 on an axis 258. The stabilizing mount242 includes a cylindrical aperture 246. The cylindrical aperture is onan axis 260.

The stabilizer mount 242 is secured to the king pin 172 as follows.Referring particularly to FIG. 12, the king pin 172 includes a thrustwasher 262. The king pin 172 is positioned in the bore 41 such that aportion of the king pin 172 extends upwardly from the cylindrical member40. The cylindrical aperture 246 of the stabilizing mount 242 ispositioned such that the king pin 172 is inserted into the cylindricalaperture 246 such that the axis 260 and the axis 171 of the king pin areaxially aligned.

In this position, the stabilizing mount 242 is secured to the king pin172 with a fastener 266 such as a screw and a flat washer and locknut.The aligned axis 260 and 171 are offset from and parallel to the axis258 of the mounting boss 256. Preferably, the offset is along an axis257 which is parallel to axis 164. In other words, as shown in FIG. 13,the axis 258 intersects the axis 257 either to the right or to the leftof the axis 171.

Referring now to FIG. 13, the king pin shock absorber 244 is shown.Preferably, the shock absorber 244 is a conventional shock absorber withequal compression and extension damping similar to small bore serieswith gas cell technology available from Arvin Ride Control of Toronto,Canada. The shock absorber 244 includes a base end 268 and a rod end270. The base end 268 is secured to the mounting boss 256 of thestabilizing mount 242 such as with a retaining ring. The rod end 270 ispivotally connected to the support frame 12 and, more particularly, tothe carriage 16. Preferably, the mounting rail 36 includes a rectangularaperture 274 spaced from the aperture 37. A mounting plate 276 isaligned with and positioned below the aperture 274. The mounting plate276 includes an upwardly extending mounting boss 278. The rod end 270 ispivotally connected to the mounting boss 278 such as with a retainingring.

In operation, as the king pin 172 rotates due to the rotation of thewheel assembly 160, the stabilizing mount 242 also rotates about theaxis 171 of the king pin 172. As the stabilizing mount 242 rotates aboutthe axis 171, the shock absorber 244 either extends or retractsdepending upon the direction of rotation of the king pin 172 due to theoffset of the axis 258 from the axis 171. Accordingly, the shockabsorber 244 functions to maintain a force on the wheel assembly 160 toprevent the wheel assembly 160 from deviating from a forward alignedpositioned in that a force to disalign the wheel assembly 160 has to begreater than the force of the shock absorber 244 maintaining the wheelassembly 160 in its forward aligned position.

The action of the shock absorber 244 maintains the wheel assembly 160 inforward alignment and also eliminates or minimizes oscillation by actingto maintain the wheel assembly 160 in its forward aligned position.

As a result of the two part support frame 12 and the wheel assembly 160,the weight of the accessory unit such as snowplow blade 144 pivots theframe 72 of the pivot frame 16 downwardly about a fulcrum consisting ofthe wheel assembly 160 thereby reducing the forces on the vehicle andurging the front end of the vehicle 46 upwardly. In the blade downposition, the weight of the accessory unit assembly 10 and the wheelassembly 160 is carried by the blade which increases the downforce by upto 80%. Preferably, the wheel assembly 160 is positioned such as to belocated between the center of gravity of the combined support frame 12,quadrant 102 and plow blade assembly 142 and the vehicle 46 and morespecifically, located close to and in the vicinity of the center ofgravity.

As a result, the weight of the accessory unit assembly 10 acts to reducethe force exerted on the front end suspension of the vehicle 46. Thishas the effect of reducing the wear on the vehicle's front endsuspension normally associated with the attachment of a accessory unit.

With reference to FIG. 1, to reduce stress on the vehicle, the downwardforce F_(HITCH) needs to be reduced or eliminated. The accessory unitassembly 10 through the use of the wheel assembly 160 eliminates thedownward force F_(HITCH). It should be noted that the accessory unitassembly 10 in the preferred embodiment eliminates the downward forceF_(HITCH) and exerts a slight upward force F_(HITCH). Specifically,

    ΣM.sub.FHitch =Plow weight(x+y)/y=F.sub.pw.

As (x+y)/y decreases, the plow weight being a constant, F_(pw)decreases. Further,

    ΣM.sub.Fpw =Plow weight(x)/y=F.sub.hitch.

As x/y decreases, the plow weight being constant, F_(hitch) decreases.

The support frame 12 consisting of the carriage 14 and the pivot frame16 and the plow mount 48 enables the vehicle mounting member 58 to bemounted further underneath the vehicle 46 in a direction away from thefront bumper. With reference to FIG. 1, this reduces the forces on thevehicle 46 since the distance y is lengthened and the distance z isshortened. Therefore, the smaller the distance z, the less effectF_(hitch) has on F_(tw). Having the mounting member 58 able to bemounted further under the vehicle 46 enhances the aesthetics of thevehicle 46 because the mounting member 58 cannot be seen at normal eyelevel.

The wheel assembly 160 also facilitates movement of the accessory unitassembly 10 when detached from the vehicle 46.

For some accessory unit applications, it may be desirable to utilize twoground engaging wheels 162 that rotate about the same axis.

We claim:
 1. An assembly for mounting an accessory unit to a vehicle,said assembly comprising:a first frame adapted to be pivotally connectedto the vehicle along a first pivot axis during operation of theassembly; a second frame pivotally connected to said first frame along asecond pivot axis, said second frame adapted to support an accessoryunit; and an actuator for actuating pivotal movement of said secondframe, said actuator operationally extending between said first frameand said second frame at a location rearward of said second pivot axisin a direction away from the vehicle.
 2. The assembly of claim 1whereinsaid accessory unit includes a plow blade; said first framecomprises a carriage frame mounted for pivotal movement on said firstpivot axis; said second frame is a pivot frame pivotally connected tosaid carriage frame at said second pivot axis, said second pivot axisbeing located forward of said first pivot axis in a direction away fromthe vehicle; said plow blade is supported by said pivot frame; anactuator operationally connecting said carriage frame and said pivotframe for actuating pivotal movement of said pivot frame relative tosaid carriage frame; and a ground engagable member secured to saidcarriage frame.
 3. The vehicle mountable snowplow assembly as set forthin claim 2 wherein said pivot frame supports said plow blade forward ofsaid second pivot axis.
 4. The vehicle mountable snowplow assembly asset forth in claim 2 wherein said carriage frame is adapted to beconnected to the vehicle rearward of said second pivot axis.
 5. Thevehicle mountable snowplow assembly as set forth in claim 2 wherein saidactuator extends between said carriage frame and said pivot frame. 6.The vehicle mountable snowplow assembly as set forth in claim 5 whereinsaid actuator extends between said carriage frame and said pivot frameat a location rearward of said second pivot axis.
 7. The vehiclemountable snowplow assembly as set forth in claim 2 wherein said groundengagable member selectively engages the ground.
 8. The vehiclemountable snowplow assembly as set forth in claims wherein said groundengagable member includes a wheel.
 9. The vehicle mountable snowplowassembly as set forth in claim 2 wherein a portion of said carriageframe extends above said pivot frame.
 10. The vehicle mountable snowplowassembly as set forth in claim 2 wherein said carriage frame includes apair of side rails, wherein each of said side rails has a first endwhich is the portion of said carriage frame pivotally connected to saidpivot frame and wherein each of said side rails has a second end adaptedto be connected to the vehicle.
 11. The vehicle mountable snowplowassembly as set forth in claim 10 wherein a pivot pin pivotally connectssaid pivot frame to said carriage frame.
 12. The vehicle mountablesnowplow assembly as set forth in claim 2 wherein said pivot frame isgenerally O-shaped.
 13. The vehicle mountable snowplow assembly as setforth in claim 12 wherein said O-shaped pivot frame is defined by twogenerally C-shaped members and wherein one of said C-shaped members isat an angle relative to the other of said C-shaped members.
 14. Thevehicle mountable snowplow assembly as set forth in claim 2 and furtherincluding a second and third actuator and wherein each of said secondand third actuators having a first end secured to said pivot frame and asecond end secured to said plow blade.
 15. The vehicle mountablesnowplow assembly as set forth in claim 2 wherein the combination ofsaid carriage frame, said pivot frame, said plow blade and said actuatorhas a center of gravity and wherein said ground engagable member issecured to said carriage frame rearward of said center of gravity. 16.The assembly as set forth in claim 1 wherein said second pivot axis isforward of said first pivot axis in a direction away from the vehicle.17. The assembly as set forth in claim 1 wherein said second frame isadapted to support said accessory unit forward of said second pivotaxis.
 18. The assembly as set forth in claim 1 wherein said first frameis adapted to be pivotally connected to the vehicle rearward of saidsecond pivot axis.
 19. The assembly as set forth in claim 1 and furtherincluding a ground engagable member connected to said first frame. 20.The assembly as set forth in claim 1 wherein said ground engagablemember selectively engages the ground.
 21. The assembly as set forth inclaim 1 wherein said ground engagable member includes a wheel.
 22. Theassembly as set forth in claim 2 wherein said wheel includes a mountingassembly that is securable to said first frame.
 23. An assembly formounting an accessory unit to a vehicle, said assembly comprising:afirst frame adapted to be pivotally connected to the vehicle duringoperation of the assembly along a first pivot axis; a ground engageablemember including a wheel and being connected to said first frame; saidground engagable member further including a spring and dampener; asecond frame pivotally connected to said first frame along a secondpivot axis, said second frame adapted to support an accessory unit; andan actuator for actuating pivotal movement of said second frame, saidactuator operationally connecting said first frame and said secondframe.
 24. The assembly as set forth in claim 1 and further includingsaid accessory unit connected to said second frame.
 25. The assembly asset forth in claim 24 wherein said accessory unit is a snowplow.
 26. Theassembly as set forth in claim 1 and further including a ground engagingwheel supported by said first frame.
 27. The assembly as set forth inclaim 1 wherein a portion of said first frame extends above said secondframe.
 28. The assembly as set forth in claim 1 wherein said actuatorincludes a hydraulic cylinder.
 29. The assembly as set forth in claim 1wherein at least one pivot pin pivotally connects said first and secondframes.
 30. The assembly as set forth in claim 1 and further including aground engagable member connected to said first frame and said accessoryunit connected to said second frame, wherein the combination of saidfirst frame, said second frame, said actuator, said accessory unit andsaid ground engagable member has a center of gravity, and wherein saidground engagable member is positioned in the vicinity of said center ofgravity.
 31. An assembly for mounting an accessory unit to a vehicle,said assembly comprising:a support frame; a first mounting memberpivotally connected to said support frame about a generally verticalfirst axis; a second mounting member connected to said first mountingmember; a ground engagable wheel connected to said second mountingmember; a spring operationally connected to said first and secondmounting members; and a dampener operationally connected to said firstand second mounting members.
 32. The assembly as set forth in claim 31wherein said dampener is a shock absorber.
 33. The assembly as set forthin claim 31 wherein said spring is a compression spring.
 34. Theassembly as set forth in claim 31 wherein said second mounting member ispivotally connected to said first mounting member along a second axis.35. The assembly as set forth in claim 34 wherein said ground engagablewheel is connected to said second mounting member at a third axis andwherein said second and third axis are parallel.
 36. The assembly as setforth in claim 31 wherein said first mounting member is removablyconnected to said support frame.
 37. The assembly as set forth in claim31 wherein said second mounting member limits the range of motion ofsaid wheel by contacting said first mounting member.
 38. The assembly asset forth in claim 31 wherein said spring limits the range of motion ofsaid wheel.
 39. The assembly as set forth in claim 31 wherein said firstmounting member includes a king pin and wherein said first mountingmember is secured to said support frame with said king pin.
 40. Theassembly as set forth in claim 31 wherein said first mounting memberincludes a pair of legs spaced such that said wheel is positionablebetween said legs and wherein said second mounting member includes apair of link arms, each link arm having a first and a second end andeach link arm is pivotally connected to one of said legs.
 41. Theassembly as set forth in claim 40 wherein said first mounting memberfurther includes a yoke secured to said pair of legs and wherein saidspring and said dampener are housed within said yoke.
 42. The assemblyas set forth in claim 31 wherein said second mounting member includes asupport member and wherein said spring and said dampener areoperationally connected to said support member.
 43. The assembly as setforth in claim 40 wherein said wheel has an axis of rotation and whereineach first end of said link arms is pivotally connected to said wheel atsaid axis of rotation.
 44. The assembly as set forth in claim 40 whereinsaid legs are pivotally connected to said link arms between said firstend and said second end of said link arms.
 45. The assembly as set forthin claim 31 and further including a shaft positioned such that saidspring surrounds said shaft, said shaft having a first end pivotallyconnected to said second mounting member whereby movement of said shaftcompresses said spring.
 46. The assembly as set forth in claim 31wherein said dampener includes a first end pivotally connected to saidsecond mounting member.
 47. An assembly for mounting an accessory unitto a vehicle, said assembly comprising:a support frame adapted to beremovably secured to a vehicle; a mounting member pivotally connectableto said support frame about a generally vertical first axis androtatable about said axis through 360 degrees; a wheel secured to saidmounting member and adapted to engage the ground; and a dampenerconnected to said support frame and said mounting member so as to dampenthe rotational movement of said mounting member with respect to saidsupport frame.
 48. The assembly as set forth in claim 47 wherein saidmounting member includes a king pin rotatable about said axis.
 49. Theassembly as set forth in claim 47 wherein said dampener is a shockabsorber.
 50. The assembly as set forth in claim 47 wherein saiddampener has a first end connected to said support frame at a secondaxis and wherein said second axis is parallel to said first axis. 51.The assembly as set forth in claim 47 wherein said dampener has a secondend operationally connected to said mounting member at a third axis andwherein said third axis is parallel to said first axis.
 52. The assemblyas set forth in claim 51 wherein said wheel rotates about a fourth axisand wherein said third axis is offset from said first axis in adirection parallel to said fourth axis.
 53. A castor wheel steeringdampening assembly comprising:a support frame; a mounting memberpivotally connectable to said support frame about a generally verticalfirst axis and rotatable about said axis through 360 degrees; a wheelsecured to said mounting member and adapted to engage the ground; and adampener connected to said support frame and said mounting member so asto dampen the rotational movement of said mounting member with respectto said support frame.